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Finding the Fourth Proportional to 543.80, 811.51 and 421.40

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Solution

The fourth proportional to 543.80, 811.51 and 421.40 is: 628.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    543.80 : 811.51 = 421.40 : x
  2. Step 2: Convert to fraction form
    543.80/811.51 = 421.40/x
  3. Step 3: Cross multiply
    543.80x = 811.51 × 421.40
  4. Step 4: Simplify right side
    543.80x = 341,970.31
  5. Step 5: Solve for x
    x = 341,970.31/543.80
  6. Step 6: Final answer
    x = 628.85

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.